In communication networks operating under the Simple Network Management Protocol (SNMP), a common index used to identify a network interface of a device is an Interface Index, or ifIndex. A device-specific algorithm typically assigns an entry in the ifIndex to an interface as the interface becomes active and the entry is removed when the interface becomes inactive. Accordingly, the ifIndex will continuously change as interface activity changes. The only method to determine an interface type or its associations with other devices within the network is to query various interface-related tables within the network in addition to the ifIndex.
The traditional method of interface indexing provides various problems. Querying multiple tables may prove time consuming for a real-time system trying to operate on a specific interface, since the system must search through a list of interfaces to find a particular interface. In addition, if performance counters are to be stored for a specific interface, the information relating to the type of interface and the relationship with other interfaces within the system must also be stored with the performance counters. This additional information is required so that subsequent examinations of historical logs will be able to determine what occurred at a specific interface at an earlier point in time. As an example, if the interface is no longer active within the system, it is not possible to learn any information about the interface solely from an ifIndex entry created when the interface was active.
If an event notification, or “trap,” is sent that identifies an interface as the source of an event, it is not possible for a human to simply look at the traditional ifIndex entry and determine immediately what the source of the event was. A human user would need software or a machine aid to translate the ifIndex entry into understandable information that identifies a specific interface. The software would have to perform a lookup by querying the SNMP device to determine additional information relating to the ifIndex entry being provided by the trap. The SNMP device may be busy, however, such as when a trap was sent because of a fault condition, making the response to the query very slow. This wait delays the timely processing of traps. Therefore, it is desirable to provide a method for encoding an interface index in order to provide ready identification.